1. Field of the Invention
The invention relates in general to a liquid crystal display panel and a driving method thereof and a liquid crystal display device using the same, and more particularly to a liquid crystal display panel having an extending electrode extending to neighboring pixel electrode and a driving method thereof and a liquid crystal display device using the same.
2. Description of the Related Art
With the great popularity of consumer electronic products in recent years, a large variety of electronic products such as mobile phone, notebook computer and liquid crystal TV has become an indispensable part for modern people in their everyday life. Particularly, the thin display device using liquid crystal display panel, having the advantages of small size, low radiation and low power consumption, has gradually taken the place of conventional CRT display device and become the priority purchase choice for consumers to choose from. Moreover, along with the advance in manufacturing process and display quality, liquid crystal display has gained great popularity in the market and further boosted the demand for liquid crystal display panel. While expanding the production capacity, the manufacturers are also dedicated to the development of large-sized panel and to the improvement in the display quality of the liquid crystal display panel so as to meet consumers' increasingly requirements.
Liquid crystal display panel displays a frame of picture by utilizing the light birefringence effect from a liquid crystal layer. Because the phase differences of the incident light passing through the liquid crystal layer from different angles are different, the birefringence effect of the light, as well as the transmittance, from certain view angle is different from that of another. Thus, the greyscale luminances of the displayed light from different view angles differ from one another. When the lights of different colors (such as red light, green light and blue light) are mixed with different luminance ratios in the upright view direction and in the inclined view direction respectively, color shift that change display color tones from different view directions will occur. In order to solve the problem, numerous wide view-angle display techinques that reduce color shift from different view angles for liquid crystal display panels are developed to increase view angles thereof.
Among these wide-angle display techniques, a method of extending an auxiliary electrode from a pixel electrode to adjacent pixel electrode and making two adjacent pixel electrodes receive voltages of different polarities (such as the dot inversion driving method or the line inversion driving method) is implemented. By the fringe field effect, which is generated between the auxiliary electrode and the pixel electrode with different voltage polarities, the alignment of liquid crystal molecules is altered, hence achieving multiple domains and increasing the view angle of the liquid crystal display panel. Referring to FIGS. 1A and 1B, FIG. 1A shows an equivalent circuit diagram of a pixel having auxiliary electrode, and FIG. 1B shows a layout diagram of pixel electrode and auxiliary electrode. A first pixel 110(n) and a second pixel 110(n+1) from numerous pixels are taken for example here. The second pixel 110(n+1) is the next pixel of the first pixel 110(n), and the first tow pixels 110(n) and 110(n+1) correspond to voltages of different polarities. The first pixel 110(n) includes a first thin film transistor TFT1 and a first pixel electrode P10, and the second pixel 110(n+1) includes a second thin film transistor TFT2 and a second pixel electrode P20. The sources of the first thin film transistor TFT1 and the second thin film transistor TFT2 are coupled to the data line 130. The gates of the first thin film transistor TFT1 and the second thin film transistor TFT2 are respectively coupled to a first scan line 120(n) and a second scan line 120(n+1). The drains of the first thin film transistor TFT1 and the second thin film transistor TFT2 are respectively coupled to the first pixel electrode P10 and the second pixel electrode P20. The first pixel electrode P10 and the second pixel electrode P20 respectively form a first liquid crystal capacitor and a second liquid crystal capacitor with the common electrode of the liquid crystal display panel. The first pixel electrode P10 has an auxiliary electrode P11 extending towards the neighboring second pixel electrode P20. The auxiliary electrode P11 is extending to be near the second pixel electrode P20. The method of driving pixel includes the following steps. First, the first thin film transistor TFT1 is enabled for charging the first pixel electrode P10 to a corresponding data voltage. The first pixel 110(n) has a first voltage polarity at this moment. Next, the second thin film transistor TFT2 is enabled for charging the second pixel electrode P20 to a corresponding data voltage. The second pixel 110(n+1) has a second voltage polarity at this moment. When the first voltage has a positive polarity and the second voltage has a negative polarity, the capacitor coupling effect between the auxiliary electrode P11 and the second pixel electrode P20 will cause a voltage drop of the first pixel electrode P10.
A circuit simulation, which is controlled under the exemplary conditions of the voltage of the common electrode being switching between 0V and 5V, the voltage of the first pixel electrode P10 during the positive half-cycle being +5V and the voltage of the first pixel electrode P10 during the negative half-cycle being −5V, is conducted. According to circuit simulation result, after the second pixel electrode P20 is charged to a corresponding data voltage, the voltage difference between the first pixel electrode P10 and the common electrode is approximately decreased to 3.5V during the positive half-cycle and decreased to 4.5V during the negative half-cycle. In general, the capacitor coupling effect between the auxiliary electrode P11 and the second pixel electrode P20 distorts the voltage of the first pixel electrode P10 and leads to the greyscale shift of the first pixel 110(n).